/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.frameworkset.commons.pool2.proxy;

import com.frameworkset.commons.pool2.KeyedObjectPool;
import com.frameworkset.commons.pool2.PoolUtils;
import com.frameworkset.commons.pool2.UsageTracking;

import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * Create a new keyed object pool where the pooled objects are wrapped in
 * proxies allowing better control of pooled objects and in particular the
 * prevention of the continued use of an object by a client after that client
 * returns the object to the pool.
 *
 * @param <K> type of the key
 * @param <V> type of the pooled object
 *
 * @since 2.0
 */
public class ProxiedKeyedObjectPool<K, V> implements KeyedObjectPool<K, V> {

    private final KeyedObjectPool<K, V> pool;
    private final ProxySource<V> proxySource;
    /**
     * Calls {@link KeyedObjectPool#addObject(Object)} with each
     * key in <code>keys</code> for <code>count</code> number of times. This has
     * the same effect as calling {@link #addObjects(Object, int)}
     * for each key in the <code>keys</code> collection.
     *
     * @param keys
     *            {@link Collection} of keys to add objects for.
     * @param count
     *            the number of idle objects to add for each <code>key</code>.
     * @throws Exception
     *             when {@link KeyedObjectPool#addObject(Object)} fails.
     * @throws IllegalArgumentException
     *             when <code>keyedPool</code>, <code>keys</code>, or any value
     *             in <code>keys</code> is <code>null</code>.
     * @see #addObjects(Object, int)
     */
    public void addObjects(final Collection<K> keys, final int count) throws Exception, IllegalArgumentException {
        if (keys == null) {
            throw new IllegalArgumentException(PoolUtils.MSG_NULL_KEYS);
        }
        final Iterator<K> iter = keys.iterator();
        while (iter.hasNext()) {
            addObjects(iter.next(), count);
        }
    }

    /**
     * Calls {@link KeyedObjectPool#addObject(Object)}
     * <code>key</code> <code>count</code> number of times.
     *
     * @param key
     *            the key to add objects for.
     * @param count
     *            the number of idle objects to add for <code>key</code>.
     * @throws Exception
     *             when {@link KeyedObjectPool#addObject(Object)} fails.
     * @throws IllegalArgumentException
     *             when <code>key</code> is <code>null</code>.
     * @since 2.8.0
     */
    public void addObjects(final K key, final int count) throws Exception, IllegalArgumentException {
        if (key == null) {
            throw new IllegalArgumentException(PoolUtils.MSG_NULL_KEY);
        }
        for (int i = 0; i < count; i++) {
            addObject(key);
        }
    }

    /**
     * Create a new proxied object pool.
     *
     * @param pool  The object pool to wrap
     * @param proxySource The source of the proxy objects
     */
    public ProxiedKeyedObjectPool(final KeyedObjectPool<K, V> pool,
            final ProxySource<V> proxySource) {
        this.pool = pool;
        this.proxySource = proxySource;
    }


    @SuppressWarnings("unchecked")
    @Override
    public V borrowObject(final K key) throws Exception, NoSuchElementException,
            IllegalStateException {
        UsageTracking<V> usageTracking = null;
        if (pool instanceof UsageTracking) {
            usageTracking = (UsageTracking<V>) pool;
        }
        final V pooledObject = pool.borrowObject(key);
        final V proxy = proxySource.createProxy(pooledObject, usageTracking);
        return proxy;
    }

    @Override
    public void returnObject(final K key, final V proxy) throws Exception {
        final V pooledObject = proxySource.resolveProxy(proxy);
        pool.returnObject(key, pooledObject);
    }

    @Override
    public void invalidateObject(final K key, final V proxy) throws Exception {
        final V pooledObject = proxySource.resolveProxy(proxy);
        pool.invalidateObject(key, pooledObject);
    }

    @Override
    public void addObject(final K key) throws Exception, IllegalStateException,
            UnsupportedOperationException {
        pool.addObject(key);
    }

    @Override
    public int getNumIdle(final K key) {
        return pool.getNumIdle(key);
    }

    @Override
    public int getNumActive(final K key) {
        return pool.getNumActive(key);
    }

    @Override
    public int getNumIdle() {
        return pool.getNumIdle();
    }

    @Override
    public int getNumActive() {
        return pool.getNumActive();
    }

    @Override
    public void clear() throws Exception, UnsupportedOperationException {
        pool.clear();
    }

    @Override
    public void clear(final K key) throws Exception, UnsupportedOperationException {
        pool.clear(key);
    }

    @Override
    public void close() {
        pool.close();
    }


    /**
     * @since 2.4.3
     */
    @Override
    public String toString() {
        final StringBuilder builder = new StringBuilder();
        builder.append("ProxiedKeyedObjectPool [pool=");
        builder.append(pool);
        builder.append(", proxySource=");
        builder.append(proxySource);
        builder.append("]");
        return builder.toString();
    }
}
